Add IRQHandler class that can be subclasses to handle an IRQ.

Also move Keyboard to a class implementation using this pattern.

Kernel/IRQHandler.cpp

@@ -0,0 +1,25 @@
+#include "IRQHandler.h"
+#include "i386.h"
+#include "PIC.h"
+
+IRQHandler::IRQHandler(byte irq)
+ : m_irqNumber(irq)
+{
+ registerIRQHandler(m_irqNumber, *this);
+}
+
+IRQHandler::~IRQHandler()
+{
+ unregisterIRQHandler(m_irqNumber, *this);
+}
+
+void IRQHandler::enableIRQ()
+{
+ PIC::enable(m_irqNumber);
+}
+
+void IRQHandler::disableIRQ()
+{
+ PIC::disable(m_irqNumber);
+}
+

Kernel/IRQHandler.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <AK/Types.h>
+
+class IRQHandler {
+public:
+ virtual ~IRQHandler();
+ virtual void handleIRQ() = 0;
+
+ byte irqNumber() const { return m_irqNumber; }
+
+ void enableIRQ();
+ void disableIRQ();
+
+protected:
+ explicit IRQHandler(byte irq);
+
+private:
+ byte m_irqNumber { 0 };
+};
+

Kernel/Keyboard.cpp

@@ -1,11 +1,10 @@
 #include "types.h"
 #include "i386.h"
 #include "IO.h"
-#include "IPC.h"
-#include "Task.h"
 #include "VGA.h"
 #include "PIC.h"
 #include "Keyboard.h"
+#include <AK/Assertions.h>
 
 #define IRQ_KEYBOARD 1
 
@@ -16,36 +15,6 @@
 #define DATA_AVAILABLE 0x01
 #define I8042_ACK 0xFA
 
-extern "C" void handleKeyboardInterrupt();
-extern "C" void keyboard_ISR();
-
-static BYTE s_ledState;
-
-asm(
- ".globl keyboard_ISR \n"
- "keyboard_ISR: \n"
- " pusha\n"
- " pushw %ds\n"
- " pushw %es\n"
- " pushw %ss\n"
- " pushw %ss\n"
- " popw %ds\n"
- " popw %es\n"
- " call handleKeyboardInterrupt\n"
- " popw %es\n"
- " popw %ds\n"
- " popa\n"
- " iret\n"
-);
-
-void handleKeyboardInterrupt()
-{
- IRQHandlerScope scope(IRQ_KEYBOARD);
- Keyboard::handleInterrupt();
-}
-
-namespace Keyboard {
-
 #define MOD_ALT 1
 #define MOD_CTRL 2
 #define MOD_SHIFT 4
@@ -66,70 +35,49 @@ static char shift_map[0x100] =
  'Z', 'X', 'C', 'V', 'B', 'N', 'M', '<', '>', '?',
 };
 
-static BYTE s_modifiers;
 
-void handleInterrupt()
+void Keyboard::handleIRQ()
 {
  while (IO::in8(0x64) & 1) {
  BYTE ch = IO::in8(0x60);
  switch (ch) {
- case 0x38: s_modifiers |= MOD_ALT; break;
- case 0xB8: s_modifiers &= ~MOD_ALT; break;
- case 0x1D: s_modifiers |= MOD_CTRL; break;
- case 0x9D: s_modifiers &= ~MOD_CTRL; break;
- case 0x2A: s_modifiers |= MOD_SHIFT; break;
- case 0xAA: s_modifiers &= ~MOD_SHIFT; break;
+ case 0x38: m_modifiers |= MOD_ALT; break;
+ case 0xB8: m_modifiers &= ~MOD_ALT; break;
+ case 0x1D: m_modifiers |= MOD_CTRL; break;
+ case 0x9D: m_modifiers &= ~MOD_CTRL; break;
+ case 0x2A: m_modifiers |= MOD_SHIFT; break;
+ case 0xAA: m_modifiers &= ~MOD_SHIFT; break;
  case 0x1C: /* enter */ kprintf("\n"); break;
  case 0xFA: /* i8042 ack */ break;
  default:
  if (ch & 0x80) {
  // key has been depressed
  break;
  }
- if (!s_modifiers)
+ if (!m_modifiers)
  kprintf("%c", map[ch]);
- else if (s_modifiers & MOD_SHIFT)
+ else if (m_modifiers & MOD_SHIFT)
  kprintf("%c", shift_map[ch]);
- else if (s_modifiers & MOD_CTRL)
+ else if (m_modifiers & MOD_CTRL)
  kprintf("^%c", shift_map[ch]);
  }
  //break;
  }
 }
 
-void initialize()
+Keyboard::Keyboard()
+ : IRQHandler(IRQ_KEYBOARD)
 {
- s_modifiers = 0;
- s_ledState = 0;
-
  // Empty the buffer of any pending data.
  // I don't care what you've been pressing until now!
  while (IO::in8(I8042_STATUS ) & DATA_AVAILABLE)
  IO::in8(I8042_BUFFER);
 
- registerInterruptHandler(IRQ_VECTOR_BASE + IRQ_KEYBOARD, keyboard_ISR);
-
- PIC::enable(IRQ_KEYBOARD);
+ enableIRQ();
 }
 
-void setLED(LED led)
+Keyboard::~Keyboard()
 {
- s_ledState |= (BYTE)led & 7;
-
- while (IO::in8(I8042_STATUS) & DATA_AVAILABLE);
- IO::out8(I8042_BUFFER, SET_LEDS);
- while (IO::in8(I8042_BUFFER) != I8042_ACK);
- IO::out8(I8042_BUFFER, s_ledState);
+ ASSERT_NOT_REACHED();
 }
 
-void unsetLED(LED led)
-{
- s_ledState &= ~((BYTE)led & 7);
-
- while (IO::in8(I8042_STATUS) & DATA_AVAILABLE);
- IO::out8(I8042_BUFFER, SET_LEDS);
- while (IO::in8(I8042_BUFFER) != I8042_ACK);
- IO::out8(I8042_BUFFER, s_ledState);
-}
-
-}

Kernel/Keyboard.h

@@ -1,16 +1,16 @@
 #pragma once
 
-namespace Keyboard {
+#include <AK/Types.h>
+#include "IRQHandler.h"
 
-enum class LED {
- ScrollLock = 1 << 0,
- NumLock = 1 << 1,
- CapsLock = 1 << 2,
-};
+class Keyboard final : public IRQHandler {
+public:
+ virtual ~Keyboard() override;
+ Keyboard();
+
+private:
+ virtual void handleIRQ() override;
 
-void initialize();
-void setLED(LED);
-void unsetLED(LED);
-void handleInterrupt();
+ byte m_modifiers { 0 };
+};
 
-}

Kernel/Makefile

@@ -19,7 +19,8 @@ KERNEL_OBJS = \
  Userspace.o \
  IDEDiskDevice.o \
  MemoryManager.o \
- Console.o
+ Console.o \
+ IRQHandler.o
 
 VFS_OBJS = \
  ../VirtualFileSystem/DiskDevice.o \

Kernel/i386.cpp

@@ -5,6 +5,8 @@
 #include "Assertions.h"
 #include "Task.h"
 #include "MemoryManager.h"
+#include "IRQHandler.h"
+#include "PIC.h"
 
 struct DescriptorTablePointer {
  WORD size;
@@ -16,6 +18,8 @@ static DescriptorTablePointer s_gdtr;
 static Descriptor* s_idt;
 static Descriptor* s_gdt;
 
+static IRQHandler** s_irqHandler;
+
 static WORD s_gdtLength;
 
 WORD allocateGDTEntry()
@@ -27,6 +31,26 @@ WORD allocateGDTEntry()
  return newGDTEntry;
 }
 
+extern "C" void handleIRQ();
+extern "C" void commonIRQEntry();
+
+asm(
+ ".globl commonIRQEntry\n"
+ "commonIRQEntry: \n"
+ " pusha\n"
+ " pushw %ds\n"
+ " pushw %es\n"
+ " pushw %ss\n"
+ " pushw %ss\n"
+ " popw %ds\n"
+ " popw %es\n"
+ " call handleIRQ\n"
+ " popw %es\n"
+ " popw %ds\n"
+ " popa\n"
+ " iret\n"
+);
+
 extern volatile dword exception_state_dump;
 extern volatile word exception_code;
 asm(
@@ -290,6 +314,20 @@ static void unimp_trap()
  HANG;
 }
 
+void registerIRQHandler(byte irq, IRQHandler& handler)
+{
+ ASSERT(!s_irqHandler[irq]);
+ s_irqHandler[irq] = &handler;
+ kprintf("irq handler for %u: %p\n", irq, &handler);
+ registerInterruptHandler(IRQ_VECTOR_BASE + irq, commonIRQEntry);
+}
+
+void unregisterIRQHandler(byte irq, IRQHandler& handler)
+{
+ ASSERT(s_irqHandler[irq] == &handler);
+ s_irqHandler[irq] = nullptr;
+}
+
 void registerInterruptHandler(BYTE index, void (*f)())
 {
  s_idt[index].low = 0x00080000 | LSW((f));
@@ -351,10 +389,37 @@ void idt_init()
 
  registerInterruptHandler(0x57, irq7_handler);
 
+ s_irqHandler = new IRQHandler*[16];
+ for (byte i = 0; i < 16; ++i) {
+ s_irqHandler[i] = nullptr;
+ }
+
  flushIDT();
 }
 
 void loadTaskRegister(WORD selector)
 {
  asm("ltr %0"::"r"(selector));
 }
+
+void handleIRQ()
+{
+ WORD isr = PIC::getISR();
+ if (!isr) {
+ kprintf("Spurious IRQ\n");
+ return;
+ }
+
+ byte irq;
+ for (byte i = 0; i < 16; ++i) {
+ if (isr & (1 << i)) {
+ irq = i;
+ break;
+ }
+ }
+
+ if (s_irqHandler[irq])
+ s_irqHandler[irq]->handleIRQ();
+ PIC::eoi(irq);
+}
+

Kernel/i386.h

@@ -55,10 +55,14 @@ union Descriptor {
  }
 } PACKED;
 
+class IRQHandler;
+
 void gdt_init();
 void idt_init();
 void registerInterruptHandler(BYTE number, void (*f)());
 void registerUserCallableInterruptHandler(BYTE number, void (*f)());
+void registerIRQHandler(BYTE number, IRQHandler&);
+void unregisterIRQHandler(BYTE number, IRQHandler&);
 void flushIDT();
 void flushGDT();
 void loadTaskRegister(WORD selector);